1. Field of Invention
The present invention relates to a coaxial cable adapter for signal transmission, which is provided with a soft rubber gasket disposed therein and has desirable waterproofness and strength.
2. Related Art
In order to connect coaxial cables on two ends, a coaxial cable adapter is usually disposed on an end portion of the cable. Referring to FIGS. 1 and 2, the structure of a first conventional coaxial cable adapter is shown. The adapter has a metal sleeve pipe 10 and an exposed plastic sleeve member 13. A movable joint 11 is disposed on an outer end of the metal sleeve pipe 10, and a sleeve barrel 12 is enchased on an inner end thereof, in which embossed grains are disposed on a central outer ring of the sleeve barrel 12 so as to be conveniently held. In an aperture of an inner end of the sleeve barrel 12, an inclined depressed ring slot 121 with a taper is opened inwards at a small distance away from the end portion. When joined to the plastic sleeve member 13, the inclined depressed ring slot 121 strongly forces the plastic sleeve member 13, such that when an end portion 131 of the plastic sleeve member 13 is inserted into the aperture of the sleeve barrel 12, the end portion 131 is pressed by the inclined depressed ring slot 121 and is thus deformed. As a result, the squeezed material at the end portion 131 of the plastic sleeve member 13 is embedded in the inclined depressed ring slot 121, and the plastic sleeve member 13 is pivoted at the end portion of the adapter. Thereby, the first conventional structure is completed.
For a second conventional structure, referring to FIG. 3, another type of an adapter is shown, and the principle of this structure is quite similar to the first one. A movable joint 30 and a sleeve barrel 32 are disposed on two ends of the adapter, and a plastic sleeve member 31 is disposed on the center. The joining between one end of the plastic sleeve member 31 and the sleeve barrel 32 is similar to the structure in FIG. 2, and the details will not be described herein again.
The aforementioned two conventional adapters have the following disadvantages in manufacturing and use.
1. In the conventional structure, the deformable plastic sleeve member is exposed, i.e., the plastic sleeve member itself is a part of the case of the adapter, so that the case of the adapter may easily crack when exposed to the sun and rain or experiencing a temperature difference for a long time.
2. As the thinner and fragile end portion of the plastic sleeve member is squeezed to be joined to the sleeve barrel, not only the strength of the joining is poor, but the joined members may easily fall off. Further, during the manufacturing, if the squeeze is forced, the plastic sleeve member usually cracks when rotationally pressed by the inclined depressed ring slot with a taper, thus resulting in rejected products, which is another disadvantage of the prior art.
3. Being a part of the case of the adapter, the plastic sleeve member has certain hardness. However, the hardness is inversely proportional to the tightness of the inner line, such that the waterproofness and adhesiveness of the adapter are poor, which is still another disadvantage of the prior art.
In view of the above, in the conventional coaxial cable adapter, the plastic sleeve member and the metal part are both disposed outside, thus causing many disadvantages. Therefore, through hard research, an inner wrapping adapter with better performance is provided to satisfy the expectation in the field.